I'll argue against that. If I want realism I'll go to work or just go outside. Games are escapism and I for one hate the trend over the last ten years or so towards more "realistic" games.

To counter that if I may, realism can help balance the different weapons in a game (even if the 'realism' isn't flawlessly accurate to real life). Otherwise the game encourages players to use weapons in a way they shouldn't be able to; as for the player it just adds a new dimension to their skill beyond the straight up point+click!